1. Field of the Invention
The present invention relates to an airbag system for a front passenger""s seat. This front passenger""s seat airbag system is arranged in an instrument panel in front of the front passenger""s seat of a vehicle.
2. Description of Related Art
The front passenger""s seat airbag system of the prior art has the modes described below for the expansion of an airbag. Specifically, the airbag protrudes at first from the instrument panel. The airbag then expands towards the rear of the vehicle along, for example, a windshield which is sloped downwards towards its front.
However, the airbag of the front passenger""s seat air bag system may be desired to satisfy the following purpose, namely, to reduce the expansion rate of the airbag towards the passenger seated on the seat, i.e., the expansion rate towards the rear of the vehicle.
An object of the present invention is to provide a front passenger""s seat airbag system capable of reducing the expansion rate of an airbag toward the rear of the vehicle.
In order to achieve this object, according to a first embodiment of the invention, there is provided a front passenger""s seat airbag system of the top-mount type arranged in an instrument panel below a windshield, comprising a door arranged on the upper face of the instrument panel, a case, and an airbag housed and held in a folded state in the case. The airbag includes a gas inlet port for injecting an inflating gas thereinto, so that the airbag is expanded, by injecting the inflating gas into the gas inlet port, towards the rear of a vehicle along the windshield while opening the door. The airbag further includes a commutator cloth arranged to cover the gas inlet port, thereby closing the two sides of the gas inlet port in the transverse direction of the vehicle, while leaving open the two sides in the longitudinal direction of the vehicle.
In order to achieve the above-specified object, according to a second embodiment of the invention, there is provided a front passenger""s seat airbag system arranged in an instrument panel, comprising a door arranged on the upper face of the instrument panel, a case, and an airbag housed and held in a folded state in the case. The airbag includes a gas inlet port for injecting an inflating gas thereinto, and a ceiling wall portion confronting the gas inlet port. The airbag is expanded, by injecting the inflating gas into the gas inlet port, towards the rear of a vehicle while opening the door. The airbag is housed in the case by arranging the ceiling wall of the airbag to closely approach the gas inlet port, subsequently by transversely folding the two edges of the airbag perpendicular to the transverse direction to closely approach the vicinity of the center of the ceiling wall, and further by longitudinally folding the left and right edges of the airbag to closely approach the vicinity of the center of the ceiling wall.
In order to achieve the above-specified object, according to a third embodiment of the invention, there is provided a front passenger""s seat airbag system arranged in an instrument panel, comprising a door arranged on the upper face of the instrument panel, a case, and an airbag housed and held in a folded state in the case. The airbag includes a gas inlet port for injecting an inflating gas thereinto, and a ceiling wall portion confronting the gas inlet port, so that the airbag is expanded by injecting the inflating gas into the gas inlet port towards the rear of a vehicle while opening the door. The airbag further includes a commutator cloth arranged to cover the gas inlet port. The airbag is housed in the case by arranging the ceiling wall of the airbag to closely approach the gas inlet port, subsequently by transversely folding the two edges of the airbag perpendicular to the transverse direction to closely approach the vicinity of the center of the ceiling wall, and further by longitudinally folding the left and right edges of the airbag to closely approach the vicinity of the center. The commutator cloth is arranged to close the two sides of the gas inlet port relative to the transverse direction of the vehicle, and to leave open the two sides of the gas inlet port relative to the longitudinal direction of the vehicle.
In the front passenger""s seat airbag system of the top-mount type according to the first embodiment of the invention, the internal pressure rises when the inflating gas is injected into the airbag at the time of expansion of the airbag. Then, the airbag pushes to open the door which is arranged on the instrument panel, until the airbag protrudes out of the instrument panel.
During expansion of the airbag, the inflating gas that flows into the airbag is branched to flow forward and backward by the commutator cloth. This quickly expands the airbag in the longitudinal direction. At this time, the front side portion protrudes towards the rear of the vehicle along the windshield. Conversely, the rear side portion protrudes towards the rear of the vehicle along the upper face of the instrument panel.
Specifically, the front side portion at the beginning of expansion extends towards the rear of the vehicle along the windshield which is sloped downward to the front. Conversely, the rear side portion at the beginning of expansion extends towards the rear of the vehicle along the upper face of the instrument panel. As a result, the airbag is expanded towards the rear of the vehicle at such a vertically large angle so as to close the space between the inner side face of the windshield and the upper face side of the instrument panel.
In the front passenger""s seat airbag system according to the first embodiment of the invention, therefore, the airbag, having protruded from the instrument panel, moves towards the rear of the vehicle at a vertically large angle, i.e., with a wide surface having a large area facing the passenger. In this mode, the airbag is not expanded to extend partially backwards. As a result, in the front passenger""s seat airbag system of the first embodiment, the expansion rate of the airbag towards the rear of the vehicle can be reduced to reduce the expansion rate of the airbag toward the passenger.
In the front passenger""s seat airbag system according to the second embodiment of the invention, the internal pressure of the airbag rises when the inflating gas flows during airbag expansion from the gas inlet port into the airbag. Then, the airbag pushes to open the door which is arranged on the instrument panel, until the airbag protrudes from the instrument panel.
At this time, the airbag, having protruded from the instrument panel, expands while extending to the two sides in the transverse direction, thereby undoing the longitudinal folding. While extended to the two sides, the airbag unfolds in the direction perpendicular to the transverse direction, thereby to undo the transverse folding.
Specifically, the airbag first extends to the two sides in the transverse direction without protruding towards the rear of the vehicle. Thus, when the airbag subsequently expands towards the rear of the vehicle, its longitudinal folding is undone to provide a surface having an enlarged wide area.
In the front passenger""s seat airbag system of the second embodiment of the invention, therefore, the airbag having protruded from the instrument panel is expanded towards the rear of the vehicle while possessing a wide surface area, which is enlarged to the two sides in the transverse direction. In the front passenger""s seat airbag system of the second embodiment, too, the expansion rate of the airbag towards the rear of the vehicle can be reduced to reduce the expansion rate of the airbag towards the passenger.
Here, the front passenger""s seat airbag system according to the second embodiment of the invention is not limited to the top-mount type, but may also be of the midway-mount type.
In the front passenger""s seat airbag system according to the third embodiment of the invention, during airbag expansion the internal pressure of the airbag rises when the inflating gas flows from the gas inlet port into the airbag. Then, the airbag pushes to open the door which is arranged on the instrument panel, until the airbag protrudes from the instrument panel.
Moreover, the airbag is expanded at first, after having protruded from the instrument panel, while being extended to the two sides in the transverse direction thereby to undo the longitudinal folding. The inflating gas that flows into the airbag is branched by the commutator cloth to flow either forward and backward perpendicular to the transverse direction, or upward and downward. As a result, the airbag quickly extends to the two sides in the direction perpendicular to the transverse direction by the commutator cloth.
In other words, the airbag expands towards the rear of the vehicle with a wide area which is extended in four directions, including not only the transverse directions but perpendicular to the transverse direction.
In the front passenger""s seat airbag system according to the third embodiment of the invention, therefore, the airbag having protruded from the instrument panel is expanded towards the rear of the vehicle with the portion on the front passenger""s side being given a wide area which is extended transversely and perpendicularly. In the front passenger""s seat airbag system of the third embodiment, therefore, the expansion rate of the airbag towards the rear of the vehicle can be reduced to reduce the expansion rate of the airbag towards the passenger.
Here, the front passenger""s seat airbag system according to the third embodiment of the invention is not be limited to the top-mount type, but may be of the midway mount type.